In the wintertime, runners in northern climates must decide whether to continue exercising outdoors or move inside to a treadmill. Running in chilly temperatures won’t cause permanent lung damage and is -- for most people -- a safe and effective workout. However, cold air can aggravate the airways, especially in certain circumstances, causing a run to become challenging in unanticipated ways.
Many people, especially new runners, believe that running in cold weather is harmful. This is simply not the case for healthy individuals. Some people even think that the lungs can actually freeze -- again, not possible, even in the coldest places on the planet. When a person takes a breath, the nose, mouth and throat warm the entering air, so that by the time it reaches the lungs, it has warmed to near body temperature.
A healthy individual won’t suffer serious respiratory issues or incur lung damage after going for a jog in the cold. However, many people experience nuisance side effects during or after running in cold temperatures. The colder the air, the drier it tends to be, so the body has to both warm and humidify each incoming breath. This causes many people, especially those who aren’t acclimated to exercising in the cold, to experience a raw, scratchy or burning feeling in the throat and windpipe. Some also report a dry cough. Simply inhaling cold air while running won’t cause an infection, but if you’re already suffering from a throat or chest ailment, running in freezing temperatures can exacerbate such conditions. Bear in mind that at excessively low temperatures – zero degrees Fahrenheit and under – the body can’t fully warm or humidify inhaled air. This may contribute to a sensation of airway constriction in otherwise healthy people.
If you plan to run in the cold, you can take certain measures to prevent annoying side effects. The nose warms and humidifies incoming air more effectively than the mouth does, so breathe through the nose rather than the mouth when possible. Wear a scarf, neck warmer or ski mask around your mouth and nose. The material will help to trap the warm, moist air that you exhale, automatically making your next breath warmer and moister. Run during the warmest hours of the day, which in winter typically occur in the early afternoon. If possible, gradually work your way up to running in increasingly colder temperatures. For instance, decrease the speed and length of your run when first running in cold weather, and progressively work back up to your regular pace and duration. Or try to run at least a few times a week throughout the fall and into the early winter, as temperatures slowly drop.
Asthmatics must exercise extra caution when running in cold weather. Both cold air and aerobic activity like running can intensify asthma symptoms, and the combination of these factors can create a dicey situation. Many runners with asthma report no issues when running in warm weather, but cold weather often triggers problems. Winter conditions can set off bronchial spasms, blocking incoming air from fully entering the lungs. Wheezing or shortness of breath soon follow and can potentially turn into a serious asthma attack. Thus, asthma suffers may want to pre-emptively take their rescue inhaler before running in the cold, and certainly ought to bring the inhaler running in case problems begin mid-workout.